1. Field of the Invention
The present invention relates to a touch pad, and in particular to a touch pad capable of increasing signal-to-noise ratio to thereby enhance its anti-jamming capability and applicability.
2. Description of Prior Art
With the rapid advancement of information technology and communication network, electronic products have been widely used in our daily life. Thus, touch pads are also developed in order to enhance the functions and utility of the electronic products. Existing touch pads are primarily divided into four categories including: resistance-type, capacitance-type, electromagnetic-type and optical-type based on their principles of sensing signals. The capacitance-type touch pad (referred to “capacitive touch pad” hereinafter) is dust-proof, fire-resistant and high-definition, so that it is widely used. The operating principle of the capacitive touch pad is described as follows. The capacitive touch pad is configured to identify the position of contact based on a change of capacitance. More specifically, the capacitive touch pad is configured to identity the coordinates of a contact point based on a change of capacitance between electrodes caused by the approach of an object (such as a finger or other conductor).
The capacitive touch pad has become a mainstream in the touch control technology and is widely used in various electronic products, such as mobile phone, panel computer, walkman, handheld electronic device (apparatus), various displayers, monitor and etc. When a finger of a user touches the capacitive touch pad provided on the aforesaid electronic product, a change of capacitance between two positions of the finger can be detected, thereby achieving a touch control effect.
Generally speaking, the capacitive touch pad is configured as a two-layer touch pad. For both layers of the touch pad, an Indium Tin Oxide (ITO) layer is formed on each transparent electrical conductive substrate by a plurality of screen printing processes or lithography processes. According to the conventional technique for the touch pad, the sensing electrode used in the touch pad is designed as a rhombus shape, and a connecting line is used to serially connect the sensing electrodes in the same axial direction. However, when used in the touch pad, the rhombus-shaped sensing electrode has a limited area covering the transparent electrical conductive substrate. As a result, the touch pad has a low signal-to-noise ratio and a poor anti-jamming capability. Thus, the prior art has the following problems including: (I) low signal-to-noise ratio; and (II) poor anti-jamming capability.
Therefore, it becomes an important issue for the present Inventor and the manufacturers in this art to solve the problems of prior art.